Structural Basis of the Frank-Starling "Law of the Heart"

The Frank Starling Law of the Heart is the major regulatory mechanism in the adult human heart that operates on a beat to beat basis. We know that it has its basis processes happening at the level of the sarcomeres in cardiac muscle tissue. These processes are called collectively "Myofilament Length Dependent Activation". How this actually works at the molecular level is not known. Here I will tell you how X-ray fiber diffraction at the BioCAT beam line 18-ID at the Advanced Photon Source, Argonne National Laboratory has led to new insights into how this fundamental physiological mechanism works.